Allyl alcohol has been mainly utilized to prepare polymer resins, medical products and fine chemical products, and is mostly derived from propylene obtained by petrochemical processes.
To overcome problems of fossil fuel exhaustion, techniques for synthesizing biodiesel from biomass, for example, vegetable or animal oil, have been commercialized, and the demand therefor is increasing.
Typically, biodiesel is produced via transesterification of vegetable oil and alcohol. In this procedure, glycerol is produced as a byproduct. This glycerol may be employed in a large amount, and is a renewable material that may be easily stored or transported, and is thus regarded as a promising material for preparation of allyl alcohol.
Preparation of allyl alcohol from glycerol is based on a two-step reaction mechanism, including a first step for dehydration of glycerol into acrolein and a second step for hydrogenation of acrolein into allyl alcohol.
In this regard, the first step is disclosed in U.S. Pat. Nos. 7,396,962, 7,655,818, 7,683,220, 7,718,829, and 7,951,978, and the second step is disclosed in U.S. Pat. Nos. 4,072,727, and 5,892,066. However, these reaction processes are complicated and difficult to carry out, and result in high separation and purification costs, and thus become unsuitable for use in industrial mass production. Moreover, such processes, which are carried out in the presence of a catalyst, are problematic because the catalyst has to be periodically replaced and high costs may result.
Direct preparation of allyl alcohol from glycerol not through acrolein is described in ChemSusChem 2012, Vol 5, pp 1401-1404, but employs a catalyst, undesirably generating byproducts such as 1,3-dihydroxyacetone. Also, as disclosed in Angew. Chem. Int. Ed. 2012, Vol 51, pp 8082-8086, the preparation process requires the use of an expensive rhenium catalyst, and is thus inappropriate for use in industrial mass production.
Although preparation of allyl alcohol from glycerol without the use of a catalyst was proposed (Kamm et al, Organic Syntheses, Coll. Vol. 1, 1941), the allyl alcohol yield was very low.
Therefore, with the goal of preparing allyl alcohol from glycerol, a byproduct of a biodiesel synthesis process, there is an urgent need for a method of preparing allyl alcohol at high yield via liquid reaction at relatively low reaction temperature without the use of a catalyst.